With rented points, there is no daily mousekeeping/towels and, as mentioned, you can't just switch dates or cancel your reservation. The
trip insurance does not reimburse you as much (about 5$ per point) should something happen.
Also, as mentioned, sleeping accomadations in the room configuration is different with
DVC. A one-bedroom gives you a king and a pull-out sofa. A 2 bedroom gives you a king, 2 queens, and a pull-out. With two hotel resort rooms, you'll likely get four queens.
DVC is currently offering DDP to renters. You pay a daily rate. This, however, could change at any time as DVC has been trying to control commercial renting. The ability of renters to use Member Services was taken away quickly and without warning, and the ability to get DDP without proof of membership could get taken away as well. There is no discount for park tickets for DVC renters.
Renting can save $$, but you will make up for the savings by not being able to deal directly with Disney and not having the luxury of switching reservations or cancelling if plans change or emergencies arise. It's up to you to decide if the savings are worth it or not.